Positive and constant-tension web letoff mechanism for textile machines



Oct. 6, 1953 G. E. CLENTIMACK 1 POSITIVE AND CONSTANT-TENSION WEB LETOFF MECHANISM FOR TEXTILE MACHINES 4 Sheets-Sheet 1 Filed April 4, 1951 INVENTOR. Geoge E. C/enfZMacK TOCt- 1953 c; E. CLENTIMACK 2,654,235

POSITIVE ANl CONSTANT-TENSION WEB LETOFF MECHANISM FOR TEXTILE MACHINES Filed April 4, 1951 4 Sheets-Sheet 2 W pq I INVENTOR. Ya Ga e E. C7en77Mac i Oct. 6, 1953 G. E. CLENTIMACK l POSITIVE AND CONSTANT-TENSION WEB LETOFF MECHANISM FOR TEXTILE MACHINES 4\ Sheets-Sheet 3 Filed April 4, 1951 lxvux'rorz. 36 15. C/e/z Whack BY //A/AI/l///A Oct. 6, 1953 G (:LENTIMACK 2,654,236

POSITIVE ANl CONSTANT-TENSION WEB LETOFF MECHANISM FOR TEXTILE MACHINES Filed April 4, 1951 4 Sheets-811991. 4

Patented Oct. 6

POSITIVE ANnncoNsrANr-frnivsron w'EB LETOFF MECHANISM FOR .TEXTILE MA- H N S Gehr 's iE- blentiuiack, Plainville, -to 'W-hitin Machine ,Works, Whitinsville,.Mass.,

.a. corporation .or Massachusetts U Application agraf 195;, saa

'11 c1; ni. (01.166486) r This inventionrelatesfltomechanism for-letting "off a yarn or other web from a -rotat able'-beam in a knitting; weaving-or othertextile machine; In such machines, it is essential that the yarn be fed to the knitting-or other fabricating device as required to produc'eth desired product'and that the web be maintainedunder constant and-substantially uniformtens'ion while thus fed.

,It is also essential that provision be made to compensate'for the gradual reduction in the outside diameterof the yarn web on th beam from which it is supplied. p A I It is the general objectjof my invention to provide animproved. mechanism for continuously and' positively letting off a 'wb from a'rotatable beam in a knitting-or weaving'or other textile machine, i

A 'further object; to provide such let-off mechanism inwhich theoperation is controlled by the difierential between two opposing fluid tensions. I also;provide improved -means;for varying the effective operating tension in predetermined relationt the gradual reduction in diameter of the web on the yarn orother' supply beam, Y

The entire mechanism is mechanical and hydraulic,- and all electricaL-electronic or other similar complications are avoided. I alsoavdid delays in response'to yarn tension changes and defects in the appearance of the -product which might be caused by starting-stopping or;speed variation in the driving'mechanism of themachine. My invention furthermlates-to arrangements and combinations of parts which wi-ll be herei-nafter described and more particularlypointed out in the appended claims. u r

A preferred for-mgof the invention is shown in the drawings, in which: a 7

)Fig. 1 a side elevation cf the-upper portion ofia machine 'embodyingmy-invention;--

Fig. 1a is-a similar view ofalower'portionof the sam machine; u

Fig. 2 is a side elevationof the let ofi or control t; Fig. 3 is a sectional plan view; taken alongthe irregular line-3 4 11; Fig.- 2.- -Referring to Figs. 1 and 1a, 'I h-ave shown-"portions of a knittingmachine 'having' u-pper and lower 'Warptbeams Biand-Br. Yarn webs Y aredrawn from the beams iB andB over tension rolls-or bars I li and M :and thence-tea flat knitting mechanism K (Fig. la) whieh' mayfibe of any usual commercial fornrand which in itself "forms no part ofmy present inventions;

:Spring's IZ and l4 (Fig.4) "provide theusu l tension "on the bars ill and- I I; and this-tension may *be' adjusted byynuts and lock nuts 16. The tensionbars wand; -H yield slightly during the knit-tingcycleto-equalizethe strains arising in the knitting operation.

--'My 'improved-l et-oif mechanism per -se is constructed asa self-contained unit within a casing 0 (Fig.3) having *aremovable cover C. One unit -U is provided for the-upper warp beam B, and-a second unit U is provided for the lower warp beam Be These-units are-identica1, and a description-of the uppenunit Uwill apply equally "to -the lower unit-U The-unit-U is shown in an inclined position, but the inclinationismerely-to facilitate access-to certain parts. l 1 ---'Powe-r for continuously operating the left-off units -'is'- preferably; derived from the usual cam shaft i211 -(Fig. la), which may be continuously rotated by a motor "Mthrough one or more driving :belts 22. I I

Asprocket' M on the'cam-shaft is connected by a chain to a spro'cket 26 on a shaft?! rotatable'inbearings-onthe 'frame-F-of the machine: Anadditional-sprocket on-the shaft 2'! 'and ofthe; same:size.as the sprocket 26 is connected Zoy aehain Z-B'and sprocket 12-9 to apower shaft 30 in-the lower-left-ofimnit U, and a third sprocket on the shaft 21 and of the same size as the sprocket 26 is ;connected by a chain 32 and sprocket 33 (Fig. 3) to a power shaft 34 in the uppen let-o'fiun-it 5 The power shafts 31! and 34 are thus icontifnu- 'ouslygrotatedand in; predetermined speed relation to the rotatio-nof the; cam-shaft 20- which controls the ti-ming of j the knitting mechanism K.

'I he power shaft 34 (Fig. *2) is connected by spiralgears fl and-31 toahollow sleeve-38 having a clutch member -40sformedat one end thereof. The sleeve =38 is rotatable infixed thrust bearings 42, and the member dfl is continuously rotated at. constant speed i. .A U .7

A: worm (EigiZDfiSIllOllllliBdDl'l a worm shaft 5!; which isrotatable in a -fixed bearing -52 and ha-lsoiina sleeve 53 which -is-axially movable but non-notatable-in a fixed bracket 54.- This sleeve may be-- securedin" axial-1yadjusted position 7 by a clamping screw 55. The shaft 5| extendsout- -ward= through--the endof the casing C and may be "turned manual-1y:whemdesired.

iThe worm .50 wmeshes wi'th a worm; gear' -lifl mounted on a stu'd fi l flxedin the casing C; and a gear 82-is rotatab1e with --the worm gear 80. The gear 62 engages a gear 64 on the yarn beam'shaft .65.'.- I he shaft -65 is rotatable in- 'fi xeol thrust bearingszfifii (Fig. 3) in the machine frame F and ssupportsxand rotates a yarn beam B (Fig. 1).

previously described. The worm shaft 5! is slid able in its bearings 52 and 53 and has a double clutch member or runner l5 fixed at its righthand end, as viewed in Fig. 2. This runner i5 is positioned between the rotating clutch member 48 and the fixed brake member '19 and with limited clearance relative to each. When the machine is in operation, all of these members are submerged in relatively heavy transmission oil.

With this construction, the runner will be rotated by the rotating clutch member 40 through the drag or pull of the oil film between these parts, and the runner 15 will be correspondingly retarded by the oil film between the runner 15 and the fixed brake member 18. The resultant rotating eifect on the runner 15 obviously depends on the exact axial position and clearance of the runner relative to the members 40 and I0.

I will now describe the device which I have provided for determining this axial position.

A rod 80 is freely slidable in the sleeve 38 previously described and at its left-hand end is seated in a center hole in the end of the worm shaft 5|. The right-hand end of the rod BI] is associated with a piston 82 slidable in a cylinder or sleeve 84.

A spring 85 is mounted in the cylinder 83 and engages the piston 82 at its left-hand end, while the right-hand end of the spring engages a plate 81 abutting the inner end of an adjusting screw 83 which has a graduated knob 89 secured thereon by a lock nut 99. The screw 88 is also threaded in a cap 92, which in turn is threaded on the outer end of the cylinder 83.

The inner end of the cylinder 83 is threaded at 93 to receive the hub 94 of a worm wheel 95. The axial position of the cylinder 83 is determined by engagement of the right-hand end of the hub 94 with the inner face of the fixed bearing 84.

Operation The operation of the let-off mechanism as thus far described will now be clearly evident.

The clutch member 40 i continuously rotated at constant speed in predetermined relation to the speed of the cam shaft 20, and simultaneously rotates the runner l5 and the worm 50 at a reduced speed determined by the oil friction or drag, which in turn is dependent on the axial position of the runner 15 relative to the clutch member 40 and to the brake member Ill.

The pull of the yarn web Y tends to rotate the worm gear 69 anti-clockwise and by direct push on the worm 59 tends to shift the shaft 5| and runner 15 to the right and to further compress the spring 85. This tends to increase the friction pull and the speed of rotation of the worm shaft 5|. 7

The spring 85 acts continuously and directly through the piston 82 and rod 80 to try to shift the runner 15 to the left in Fig. 2, thus increasing the braking effect, decreasing the driving tension, and slowing down the rotation of the runer l5 and worm 50.

If the tension in the yarn web Y is increased, it will thus shift the worm 50 and runner 15 to the right in Fig. 2 and will thereby increase the liquid drag or pull of the clutch member 40 and correspondingly increase the speed of rotation of the worm 50. This increases the rate of let-off and promptly relieves the increased yarn web tension. As the excess yarn tension is relieved,

'the spring returns the runner 15 to its normal running position and balanced clearance. If the yarn web becomes slack, the spring 85 shifts the runner 15 to the left to decrease the rate of letoff.

The yarn web is thus let off at a substantially constant speed and in definite relation to the speed of the cam shaft, but at the same time the rate of let-off will be temporarily increased or decreased to correct Variations in web tension as they may occur. As the yarn web is let off in the direction of yarn pull, the load on the tension units U and U is relatively small.

Adjustment for yarn beam diameter It will be obvious that the speed of let-off rotation of the yarn beam shaft 65 must be increased as the diameter of the web on the beam decreases, and it will also be obvious that the tension of the yarn eb transmitted through the gears 64 and 62 and the worm gear 58 to the worm 58 will act at an increasing mechanical. disadvantage, as the decrease in diameter of the yarn web correspondingly reduces the radius of the point of application of the yarn tension to the gear train.

In order to ofiset these dual and cumulative effects, I have made special provision for reducing the compression of the spring 85 as the diameter of the web on the yarn beam decreases, and I will now describe the devices by which this is accomplished.

The worm wheel (Fig. 2) previously described is engaged by a worm I09 (Fig. 3) mounted on a worm shaft illl rotatable in fixed bearings in the casing C and cover C. The front end of the shaft [0i extends through the cover and may be slotted so that it can be conveniently turned for manual adjustment.

A ratchet IE3 (Fig. 2) is fixed on the shaft HH and is engaged by a pawl m5 mounted on a forked or slotted arm E56 which embraces the shaft lfll and is both angularly and radially movable relative thereto. A spring [0? yieldingly holds the pawl I05 in engagement with the ratchet I03.

The upper end of the arm [D5 is pivoted at I III to a link HI having its left-hand end portion (Fig. 2) slotted at H2 to embrace a cam shaft H4. A cam H5 is mounted on the shaft H4 and the link HI has a pin H1 which is held in engagement with the cam H5 by a tension spring H8.

As the cam I I5 rotates, the ratchet 183 will be correspondingly advanced," thus giving the worm gear 95 an angular movement which will allow the cylinder 83 to slide further toward the right in Fig. 2, and correspondingly reducing the compression of the spring 85.

When the pin I H passes off of the point of the cam H5, the arm I06 and associated pawl I05 receive a return or idle movement to the right until the arm engages the end of an adjusting screw I20. The amount of feed of the ratchet 03 for each oscillation of the arm W6 is determined by the setting of the adjusting screw [20. The further the screw is advanced into the casing 0, the less teeth the pawl I05 will take on each oscillation.

Provision is made for raising the pawl I05 out of engagement with the ratchet I03 when it is desired to turn the shaft IOI manually backward fo ad n or re etfin 7's thi P 199 a collar I22 (Fig. {2) 18111011111756. on arstu'd I23 e di freely u ar th ou a up e iwal' of the casing-C and having "aknob -I 25"threa'ded thereon. The link III is freely :slidableithroug'h the'collar I22. flvfanualrotation'iof'the knob "I 25 will raise the collar IZZ which "in' turn '"will lift the link "I i i and raise "the pawl "I to 'clear the ratchet res and thus permit "manual "reverse movement of the worm .shaft IOI.

'The cam shaft 114 (Fig.2) has a ratchet I30 engaged by a feed-pawl I3I and-,aholding pawl I32, each held in yielding engagement with "the ratchet by a spring I-33. -The holding pawl I32 is mounted on a fixed stud-13 but the feed .pawl -fiI 3iI is pivoted at I36 to afeed lever I31 which 'ismounted to swing aboutthe axis of :;th e. .cam Shaft H4.

Th i ed ev wlil e fi is n a ed ibva cam I40, which ismounted on the yarn beam shaft 65 and rotates with thegear 64. A spring I42 tends to move thele ver IB'I toward the cam 4-40, and the extent of movement isadeter- --mined by an adjusting screw l fl thread-ed the casing C and engaging a laterally projecting arm I46 on the lever I37. The extent of idle return movement of the feed pawl I3I is determined by the adjustment of the screw I45, as in the similar ratchet feed previously described.

Each complete revolution of the yarn beam shaft 65 and its associated yarn beam will rotate the cam I40 and give the feed lever I31 and feed pawl I3I a feeding movement, the extent of which is determined by the adjusting screw I45. Each complete revolution of the ratchet I30 and associated cam shaft H4 and cam II5 will give the arm I06 and feed pawl I05 an oscillating feeding movement, which in turn is determined by the setting of the adjusting screw I20. Such movement, as previously described, will effect progressive reduction of the compression of the spring 85, so that progressive reduction in yarn web diameter will effect axial shifting of the runner I5 and a corresponding increase in runner speed.

The initial compression of the spring 85 may be determined by turning the graduated disc 89, and the rate of correction for reduction in yarn web diameter may be experimentally determined by the setting of the adjusting screws I45 and I20 and with due regard to the size or diameter of the yarn.

It should be particularly noted that the force which turns the runner I5 and thus acts to let off the yarn web, is not a direct force, but is a differential force determined by the fluid friction pull of the constantly rotating clutch member 40, and the fluid friction drag of the fixed brake member I0.

It is found in actual use that ordinary changes in temperature or viscosity of the transmission oil do not materially effect the operation of this let-01f mechanism, as the differential pull which rotates the worm 50 is substantially independent of such temperature or viscosity changes.

Having thus described my invention and the advantages thereof, I do not wish to be limited to the details herein disclosed, otherwise than as set forth in the claims, but what I claim is:

l. A let-off mechanism for a textile machine having a rotated yarn supply comprising a driven shaft, speed-reducing connections between said shaft and said rotating yarn supply, a continuously rotated drying shaft, a clutch member thereon, an opposed stationary brake ass having a rotated yarn supply comprising-a driven shaft, speed-reducing connections -=between said shaft and said rotating yarn supply, a --con-' jtinuously rotated drivi-n g shaft, a elut'chmem- "ber therein, "an opposed stationary brake "member, arr-inner connected to said 'dri'ven shaft and positioned between said rotating clutchmember and said stationary brake member, said shafts and associated ,p'arts -b'eing 'fimmersed "in trans- "mission oil, said runner "and driven shaft being rotatedby the excess of the oil-transmittedpull :of the clutch member overthe oil-transmitted drag of-the brake-member,-and meanstovary the proportionate clearance ;of said 'runnerrela- -tive to said clutch -;member; and said brakememher.

3. A let-01f mechanism for a textile machine having a rotated yarn supply comprising a driven shaft, speed-reducing connections between said shaft and said rotating yarn supply, a continuously rotated driving shaft, a clutch member thereon, an opposed stationary brake member, a runner connected to said driven shaft and positioned between said rotating clutch member and said stationary brake member, said shafts and associated parts being immersed in transmission oil, said runner and driven shaft being rotated by the excess of the oil-transmitted pull of the clutch member over the oil-transmitted drag of the brake member, the spacing of said clutch member and said brake member being axially fixed, and said runner being axially shiftable between said members.

4. The combination in a let-01f mechanism as set forth in claim 3, in which means is provided. to shift the runner axially in response to changes. in let-01f tension in said machine.

5. The combination in a let-01f mechanism as set forth in claim 3, in which means is provided to shift the runner axially in response to changes in let-01f tension in said machine, and in which means is provided to vary the amount of axial shift of said runner for a given change in yarn tension in predetermined relation to the reduce tion in diameter of said yarn supply.

6. The combination in a let-off mechanism as set forth in claim 3, in which means is provided to shift the runner axially in response to changes in let-off tension in said machine, and in which said latter means includes a spring resistant to axial shifting of the runner toward the rotating clutch member.

'7. The combination in a let-01f mechanism as set forth in claim 3, in which means is provided to shift the runner axially in response to changes in let-off tension in said machine, and in which said latter means includes a spring resistant to axial shifting of the runner toward the rotating clutch member, and means to decrease the resistance of th spring to such axial shifting of the runner for a given change in yarn tension.

8. The combination in a let-off mechanism as set forth in claim 3, in which means is provided to shift the runner axially in response to changes in let-off tension in said machine, and in which said latter means includes a spring resistant to axial shifting of the runner toward the rotating clutch member, and means to decrease the resistance of the spring to such axial shifting of the runner for a given chan e in yarn tension and in proportion to the reduction in diameter of the yarn supply.

9. The combination in a let-ofi mechanism as set forth in claim 3, in which means is provided to shift the runner axially in response to changes in let-01f tension in said machine, and in which said latter means includes a spring resistant to axial shifting of the runner toward the rotating clutch member, and means to decrease the resistance of the spring to such axial shifting of the runner for a given change in yarn tension and in proportion to the reduction in diameter of the yarn supply, and said latter means being directly actuated with said rotating yarn supply.

10. The combination in a let-ofi mechanism as set forth in claim 3, in which means is provided to shift the runner axially in response to changes in let-ofi tension in said machine, and in which said latter means includes a spring resistant to axial shifting of the runner toward the rotating clutch member, manual means to adjust the initial resistance of said spring, and means to decrease the resistance of the spring to such axial shifting of the runner for a given change in yarn tension and in proportion to the reduction in diameter of the yarn supply.

11. The combination in a let-off mechanism as set forth in claim 10, in which means is provided to vary the rate of decrease of spring resistance for a given change in the diameter of the yarn pp y- GEORGE E. CLENTIMACK.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,100,680 Wirth Nov. 30, 1937 2,450,489 Sepavich et a1. Oct. 5, 1948 2,529,241 Bassist Nov. 7, 1950 2,539,296 Clentimack Jan. 23, 1951 FOREIGN PATENTS Number Country Date 423,222 Great Britain Jan. 28, 1935 624,642 Germany Jan. 25, 1936 

